When the TAC module detects a fault within the TAC system, it may set more than one code. This is due to the redundant tests run continuously on this system. Locating and repairing a single fault may correct more than one code. Keep this in mind as you review the Captured Info available with a Scan Tool.

Refer to the related TAC System trouble codes

Trouble Code: P1133

HO2S-11 (Bank 1 Sensor 1) Insufficient Switching

Possible Causes:

Air leaks present in the exhaust manifold or the exhaust pipes

Fuel pressure is too high (i.e., causing a rich air fuel mixture)

HO2S may be contaminated (due to improper fuel or silicone)

HO2S signal high or low reference circuit has high resistance

HO2S heater element has failed, or the heater circuit is open

PCM has failed

Trouble Code: P1134

HO2S-11 (Bank 1 Sensor 1) Transition Time Ratio

Possible Causes:

Air leaks present in the exhaust manifold or the exhaust pipes

HO2S may be contaminated (due to improper fuel or silicone)

HO2S signal low reference circuit has high resistance

HO2S heater element has failed, or the heater circuit is open

PCM has failed

Trouble Code: P1153

HO2S-21 (Bank 2 Sensor 1) Insufficient Switching

Possible Causes:

Air leaks present in the exhaust manifold or the exhaust pipes

Fuel pressure is too high (i.e., causing a rich air fuel mixture)

HO2S may be contaminated (due to improper fuel or silicone)

HO2S signal high or low reference circuit has high resistance

HO2S heater element has failed, or the heater circuit is open

PCM has failed

Trouble Code: P1154

HO2S-21 (Bank 2 Sensor 1) Transition Time Ratio

Possible Causes:

Air leaks present in the exhaust manifold or the exhaust pipes

HO2S may be contaminated (due to improper fuel or silicone)

HO2S signal low reference circuit has high resistance

HO2S heater element has failed, or the heater circuit is open

PCM has failed

Trouble Code: P1201

Gas Mass Sensor Range/Performance

Possible Causes:

Air filter or air inlet duct is clogged or restricted

Air leaks in the exhaust pipes or manifold, or the HO2S location

Base engine problem (i.e., engine compression, vacuum leak)

CNG system fuel pressure is incorrect

PCV system problem (i.e., PCV vacuum hose or valve leaking)

EVAP canister purge system malfunction

Gasoline contaminated engine oil

Fuel pressure regulator damage or leaking

PCM has failed

Trouble Code: P1207

FICM PWM Signal To PCM Circuit Malfunction

Possible Causes:

FICM sensor PWM signal circuit is open or shorted to ground

FICM is damaged or it has failed

PCM has failed

Trouble Code: P1215

High Pressure Or Low Pressure Lockout, MIL, NGO Circuit Malfunction

Possible Causes:

Natural Gas Output Enable, High Pressure Lockout, Low Pressure Lockout or MIL control circuit is open, shorted to ground or shorted to system power

Alternative Fuels ECU is damaged or has failed

Trouble Code: P1220

TP Sensor 2 Circuit Malfunction

Possible Causes:

TP2 sensor signal circuit is open, shorted to ground or to power

TP2 sensor VREF circuit is open, shorted to ground or shorted to system power (B+)